**8.1 Calibration aspects for network model and verification**

In order to verify the computing results the network should be calibrated first. This means in the initial phase the simulation results must be compared with and validated against measurements taken in the field, e.g. pressure at selected (better many) control points. In most cases the network points which have appropriate measurements are sparsely installed. Calibration is a project that needs an extra effort and maybe temporary installation of additional measurements. If calibration is omitted then the computed/simulation results could be uncertain at a (small) percentage in a specific area (of few measurement points). Pipeline roughness value is another value that is often not really known but estimated, only. Instead, an "integral" roughness value is used for the pipes which averages individual values and some small scale effects on flow (e.g. sharp bendings).

**8** 

*Algeria* 

**Production of Biogas from Sludge Waste and** 

The pollution of water, air and soil by municipal, industrial and agricultural wastes is a major concern of public autorithies who imperatively have to encourage the development of effective and non expensive treatment technologies. Although it is not recent, the process based on the anaerobic digestion (bio-methanisation) for the treatment of the waste organic fraction, is getting very attractive from the environmental and the economical points of view. It consists of a biological degradation of the organic matter, under anaerobic conditions, where a biogas, mainly methane (CH4) is evolved, and hence providing a renewable source of energy which may be used in the production of electricity and heat.

Generally various types of residual sludges and solid wastes are generated by human activities. They are composed of organic matter which may or may not be easily biodegradeable, inorganic matter, inert soluble and non soluble matter, toxic matter, etc. In order to treat these solid wastes, it is first required to characterise them and second to choose a treatment mode depending on their types and their possible final destinations. According to the physical state, one may distinguish solid wastes (dehydrated sludges, domestic wastes, etc.), liquid wastes (effluents from food, fresh liquid sludges, etc.) and suspensions (sludges from water treatment plant). Classification in terms of the sources may

• Biomass and organic wastes: these are potential biodegrable materials since they are made of natural organic molecules which may be inserted into the biogeochemical of the matter, particularly the carbone cycle. Industrial wastes can be concerned since they

• Agriculture and food wastes such as manure and other wastes from breeding. The treatment of these wastes in treatment plants generate sludges rich in organic matter

• Municipal wastes which include domestic wastes and other types depending on the mode and nature of the collection: from small and moderate industrial units, public spaces, etc. They represent a good fraction of fermentable ready to undergo a biological treatment. • Sludges from municipal wastewaters treatment plants: these are the main wastes produced by a treatment plant and are mainly constitued of dead bacteria and

and hence are potentially biodegradable , requiring adapted methods.

have non negligeable organic matter concentrations.

**1. Introduction** 

be as follows:

**Organic Fraction of Municipal Solid Waste** 

Derbal Kerroum, Bencheikh-LeHocine Mossaab

and Meniai Abdesslam Hassen *University Mentouri Constantine,* 
